\documentclass{article}
\usepackage{amssymb,amsmath,amscd,concmath}
\pagestyle{empty}
\begin{document}
\begin{equation*}\mathbf{j}\mathbf{k} = \mathbf{j}(\mathbf{i}\mathbf{j}) = \mathbf{j}(-\mathbf{j}\mathbf{i}) = \mathbf{i}\end{equation*}
\end{document}
